Historians who do research, how do you find/use your resources?

Obviously this depends largely on the field you're looking into. However, I can kind of give my analysis of how I know of or will look for sources.

For me you generally learn about the "large" players while taking a course of multiple courses when in University. There tends to be sometimes these "tomes" of a certain historiography, that then branch off from there. An example would be Robert Conquest's "Harvest of Sorrow" for research into the holodomor or his book The Great Terror for information on the great terror (obvious name is obvious). The problem is, how do you find these out if you're not taking a course on the subject? I mean, we have a great resource here in our Wiki, but without such help or without asking for good starter resources from a historian (here or at schools), there tends to be a gap in accessible knowledge. It doesn't help that certain historians won't recommend certain books, or prefer other books. Sometimes the cornerstone book isn't very accessible or is now out of date. Therefore, if I was looking into a subject I would do a few things:

First I would use wikipedia. Yes, the thing most historians despise. However, there is a trove of information not in the body of the text, but instead in the other parts of the page on the subject. Most times at the bottom is a list of citations, use these to find more detailed books about the subject you are interested in. Look for a Bibliography if the page has one. Once you find that then start looking for authors and books that are attached to reputable publishing houses. For example, Harvard, Oxford, and Cambridge are usually the top tier for most subjects. There are others too. The key is to look for something you can recognize also. Stay clear of bigger, more mainstream publishers; stick to the academic ones. Mainstream publishers may be okay, but often they are for a more casual audience and do not have as much academic rigor attached.
If a subject is more general or maybe more specific seek out syllabus from Professors at Universities. A recent trend has been placing syllabi online. In them seek out the required reading, or the book list, or what is on "reserve." Even better is to be both these first two steps and see if you see a pattern. You can usually find them using Google by searching "Topic Syllabus"
Use a librarian. Often there is Subject Librarians at university libraries. These librarians are normally masters in that specific field or know the trends in the field they study in. They may also have a feel for what their professors are using in those subject classes. Often you can use a nearby university even if you're not a student.
Once you have one book, see what is in the back. See what sources the book author used. Seek out other books you see listed. A works cited and a bibliography is something the author spent a lot of time investigating. Other times the historian will directly reference another book/author in the body. Keep a note of who the author is necessarily critiquing. These are sometimes found in the introduction of the book.
Check reviews from other academic papers/journals. Often times the authors reviewing a new book is a Professor/author of a closely related book. Use their names to find more books on the subject.

So to summarize: Check Wikipedia for their bibliographies, check those with publicly available syllabi, use local resources, check reviews. Keep notes.

Now, how to use them? That can depend on the content and what you're using them for. For essays that means using a bibliography or works cited. Other times it means just reading and engrossing yourself into the subject. If you had more specific ways to use sources, I can definitely answer that as well.